This paper considers the ways in which Leon Petrażycki and Eugen Ehrlich employed the psychological notion of emotions in defining the law. Both scholars defined the law by referring to special kinds of emotions: bilateral emotions in Petrażycki's conception and repulsive emotions of experiencing the wrong behavior of other people, according to Ehrlich's legal sociology. On the basis of a comparison between the theories of Petrażycki and Ehrlich, the author asserts that both theories hinge on similar methodologies and philosophies. This approach has evident affinities with the conception of law developed by Axel Hägerström and other Scandinavian realists. This analysis suggests a parallel in the development of the realist, sociological and psychological approaches to the law in the first decades of the twentieth century, uncovering certain trends in legal scholarship that underpinned this development.